AXIAL FLOW FAN WITH BLADES TWISTED ACCORDING TO A BLADE PITCH RATIO THAT DECREASES (QUASI) LINEARLY WITH THE RADIAL POSITION

摘要

An axial flow fan (1) is disclosed comprising a hub (3),an annular shroud (6) extending concentric with the axis (4) of the hub (3), and a plurality of fan blades (2) connected at a root end (11) to said hub (3) and having a free tip end (7) extending radially towards said shroud (6), wherein the blades (2) are designed so that the fan (1) when in operation at nominal operating conditions generates a fluid flow in the immediate vicinity after the blades (2) which comprises a core flow that substantially is a forced vortex flow where the tangential flow speed component (c₂, _u) is proportional with the radial distance (r) from the axis (4). Equations to define the chord angle θ of the blades (2) are provided.